Legal claims defining the scope of protection. Each claim is shown in both the original legal language and a plain English translation.
1. A processor for facilitating a method for performing garbage collection of an index block of a non-volatile memory, the index block including index pages that store logical-to-physical mappings of data pages, the method comprising: determining that an index page has an uncorrectable error during garbage collection of the index block, the uncorrectable error preventing the logical-to-physical mapping contained in the index page from being reconstructed in a new index block; accessing a data structure in volatile memory to determine if the data structure contains the logical-to-physical mapping of the index page; determining whether the data structure has the logical-to-physical mapping of the index page; in response to determining that the data structure does have the logical-to-physical mapping of the index page, reconstructing the index page using the logical-to-physical mapping from the data structure in a new index block; and in response to determining that the data structure does not have the logical-to-physical mapping of the index page, performing a restore operation to obtain the logical-to-physical mapping of the index page; and using the logical-to-physical mapping obtained from the restore operation to reconstruct the index page in the new index block.
During garbage collection of an index block in non-volatile memory (like flash), this system handles uncorrectable errors in index pages. These index pages map logical addresses to physical addresses of data pages. The processor detects an uncorrectable error in an index page, preventing reconstruction of its mappings. It then checks a volatile memory data structure (like RAM) for the missing logical-to-physical mapping. If found, the index page is reconstructed in a new index block using this mapping. If the mapping is not in the RAM data structure, a restore operation (like rebooting or a page-specific restore) is performed to recover the mapping, and then the index page is reconstructed in the new index block.
2. The processor of claim 1 , wherein the restore operation is a reboot operation.
The processor for handling garbage collection errors, as described in claim 1, uses a reboot operation as the restore operation to obtain the logical-to-physical mapping of the index page when the data structure in volatile memory doesn't contain the needed mapping during garbage collection. This ensures that even if an uncorrectable error occurs and the RAM data structure lacks the mapping, the system can still recover the mapping through a full system restart, enabling reconstruction of the corrupted index page and continued operation.
3. The processor of claim 1 , wherein the restore operation is a page specific restore operation or a block restore operation.
The processor for handling garbage collection errors, as described in claim 1, uses either a page-specific restore operation or a block restore operation as the restore operation. If the data structure in volatile memory doesn't contain the needed mapping during garbage collection, the system tries a targeted recovery before resorting to a full reboot. A page-specific restore attempts to recover only the specific corrupted index page, while a block restore recovers the entire index block containing the corrupted page.
4. The processor of claim 1 , wherein the data structure is a tree that stores physical addresses of pages in a compressed form.
The processor for handling garbage collection errors, as described in claim 1, uses a tree data structure in volatile memory to store physical addresses of pages in a compressed form. This tree structure is used to find the logical-to-physical mapping of an index page that has an uncorrectable error during garbage collection. The compressed format allows for efficient storage and lookup of mappings, reducing memory overhead while facilitating fast recovery of lost mappings.
5. The processor of claim 1 , wherein the determining that an index pale has an uncorrectable error during garbage collection of the index block comprises: determining the index page number of the index page; translating the index page number into a logical address by taking the product of the index page number and an index page ratio; and using the logical address to access at least one node in the data structure, the at least one node potentially containing the logical-to-physical mapping of the index page.
The processor for handling garbage collection errors, as described in claim 1, determines that an index page has an uncorrectable error by first finding the index page number. It then translates this number into a logical address by multiplying it by an index page ratio (pages per block). This logical address is then used to access a node (or nodes) within the volatile memory data structure (potentially a tree). This node *may* contain the logical-to-physical mapping needed to reconstruct the index page.
6. The processor of claim 1 , wherein the data structure is a tree data structure, and wherein the determining comprises performing an exhaustive search of the tree data structure to locate the logical-to-physical mapping of the index page.
The processor for handling garbage collection errors, as described in claim 1, uses a tree data structure and performs an exhaustive search of it to find the logical-to-physical mapping of the index page when an uncorrectable error is found during garbage collection. If the mapping isn't found quickly, the system searches the *entire* tree to make sure that the mapping is nowhere in the volatile memory data structure before it falls back to a restore operation (like a reboot).
7. A memory interface for accessing a non-volatile memory, the non-volatile memory comprising index blocks, each index block comprising index pages that map logical-to-physical addresses of data pages, the memory interface comprising: a bus controller for communicating with the non-volatile memory; and control circuitry operative to direct the bus controller to perform a garbage collection operation on an index block, the control circuitry further operative to: determine which index pages in the index block are valid index pages; for a valid index page, determine whether a data structure held in volatile memory has the logical-to-physical mappings of the valid index page; in response to determining that the data structure has the logical-to-physical mappings of the valid index page, reconstruct the valid index page in a new index block using the logical-to-physical mappings from the data structure; and in response to determining that the data structure does not have the logical-to-physical mapping of the valid index page, execute one of: a reconstruction operation to reconstruct the valid index page in the new index block if the valid index page can be read, and a restore operation to obtain the logical-to-physical mapping of the index page if the valid index page cannot be read.
A memory interface manages a non-volatile memory (like flash) with index blocks containing index pages that map logical to physical addresses. A bus controller communicates with the memory. Control circuitry directs the bus controller to garbage collect an index block, determining which index pages are valid. For valid pages, it checks a volatile memory data structure for logical-to-physical mappings. If found, the index page is reconstructed in a new index block using those mappings. If not found, it either reconstructs the index page if readable or performs a restore operation (e.g., reboot) to get the mapping if unreadable.
8. The memory interface of claim 7 , wherein the control circuitry is further operative to use the logical-to-physical mapping obtained from the restore operation to reconstruct the index page in the new index block.
The memory interface, as described in claim 7, uses the logical-to-physical mapping obtained from the restore operation to reconstruct the index page in the new index block. After the restore operation (such as a reboot, a page-specific restore, or a block restore) provides the missing logical-to-physical mapping, the control circuitry utilizes this recovered information to rebuild the damaged index page within the new index block, thus maintaining data integrity and system functionality.
9. The memory interface of claim 7 , wherein the data structure includes a tree of a logical-to-physical mapping.
The memory interface described in claim 7 uses a data structure that includes a tree to store logical-to-physical mappings. This tree-like structure facilitates efficient searching and retrieval of the correct physical address corresponding to a given logical address, aiding in the recovery process during garbage collection when a valid index page's mapping is not immediately available.
10. The memory interface of claim 7 , wherein the restore operation is a reboot operation.
The memory interface, as described in claim 7, uses a reboot operation as the restore operation. When the volatile memory data structure lacks the required logical-to-physical mapping for a valid index page during garbage collection, the control circuitry initiates a complete system reboot to re-establish the mappings and enable the reconstruction of the index page in the new index block.
11. The memory interface of claim 7 , wherein the restore operation is a page specific restore operation or a block restore operation.
The memory interface, as described in claim 7, uses either a page-specific restore operation or a block restore operation as the restore operation. This allows the system to attempt a more targeted recovery of the logical-to-physical mapping when the volatile memory data structure doesn't contain the needed mapping during garbage collection, before resorting to a full reboot.
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August 19, 2014
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